This application is based on application Nos. 10-1999-0051646 and 10-2000-0014837 filed in the Korean Industrial Property Office on Nov. 19, 1999 and Mar. 23, 2000 respectively, the contents of which are incorporated hereinto by reference.
(a) Field of the Invention
The present invention relates to methods and pharmaceutical compositions for treating alopecia and promoting hair growth using nonimmunosuppressive [xcex3-hydroxy-methylleucine4] cyclosporin A.
(b) Description of the Related Art
Approximately 100,000 to 150,000 hairs exist on a human body, each hair growing and falling out through the different cycles of anagen, catagen, and telogen. These cycles are repeated every 3 to 6 years resulting in a normal loss of 50 to 100 hairs per day, on average. Alopecia generally means that the proportion of hairs in the anagen cycle is decreased, and the proportion of hairs in the telogen or catagen cycles is increased, so many hairs abnormally fall out. These situations include male pattern alopecia, alopecia senilis, alopecia areata etc.
Factors such as poor blood circulation toward hair follicle, excessive male sex hormone, seborrhea, scalp function deterioration due to peroxides, bacteria, etc., hereditary factors, aging, and stress are often given as reasons for the alopecia, but explicit reasons have not been identified thus far.
A preparation containing minoxidil, which is the most widely used medication thus far in the treatment or prevention of alopecia, is one of two hair-restorers which have received U.S. Food and Drug Administration authorization so far. Even though minoxidil was developed as a medication for reducing blood pressure, it is now more famous as a hair-restorer because of the trichological activity that occurs owing to its side effects. Although the hair growth-stimulating mechanisms of minoxidil have not yet been fully discovered, blood flow increase through vasodilatation effects is thought to be supplying nutrition to the hair roots, thus promoting hair growth. This blood flow increase model is indirectly validated by the recent report that minoxidil increases the expression of VEGF (vascular endothelial growth factor), a growth factor related to vasodilatation, at the dermal papilla which is a major cell forming the hair root (Br. J. of Dermatol., 1998; 138; 407-411). Furthermore, dermal papilla cell activation of hair roots (Skin Pharmacol., 1996; 9; 3-8), and studies showing that hair follicle growth is promoted in the hair follicle tissue culture (e.g. J. Invest. Dermatol., 1989; 92; 315-320), in addition to the vasodilatation effects in the hair growth-stimulating effect mechanisms of minoxidil, suggest that minoxidil can act as a direct growth factor.
Additionally, the Merck Corporation""s recently commercially available Propecia, principal ingredient being finasteride, inhibits the transformation of male sex hormone testosterone into dehydrotestosterone, a more potent male sex hormone. Although it became clear that finasteride showed notable effects on male pattern, side effects of partial suppression for male sex function have been reported (J. Am. Acad. Dermatol., 1998; 39; 578-589).
It has been reported that cyclosporin is not only a representative immunosuppressant, but it also brings about various physiological effects such as nephrotoxicity, hepatotoxicity, high blood pressure, hair growth-stimulating effect, gingival over growth, and antimicrobial effects against for viruses, fungi, and protozoa (Advances in Pharmacol., 1996; 35; 114-246 and Drug Safety, 1994; 10;310-317). A representive cyclosporin A is shown in the following Structural Formula 1 as a cyclic peptide with 11 amino acids comprising various N-methyl amino acids, and D-alanine at the No. 8 position. 
where MeBmt is N-methyl-(4R)-4-[(E)-2-butenyl]-4-methyl-L-threonine; Abu is L-aminobutyric acid; Sar is sarcosine; MeLeu is N-methyl-L-leucine; Val is L-valine; Ala is L-alanine; DAla is D-alanine; and MeVal is N-methyl-L-valine. Amino acid form of the above cyclosporin A has a L-configuration, unless otherwise specified.
Possibilities for the development of cyclosporin as a new hair growth stimulator using excessive hair growth side effects have been reviewed in a variety of studies. Among them, animal hair growth-stimulating tests (Arch, Dermatol. Res., 1996; 288; 408-410), human alopecia areata (J. Am. Acad. Dermatol., 1990; 22; 242-250), human male pattern alopecia (J. Am. Acad. Dermatol., 1990; 22; 251-253 and Skin Pharmacol., 1994; 7; 101-104), and protection from chemotherapy-induced alopecia (Clin. Lab. Invest., 1995; 190; 192-196 and J. Pathol., 1997: 150; 1433-1441) have been reported.
Several patents disclosed the use of cyclosporins and related derivatives for hair revitalization (Japanese Laid-open Patent Publication Nos. Showa 60-243008, Showa 62-19512, and Showa 62-19513, a cyclosporin derivative with the No. 8 position changed in European Laid-open Patent Publication No. 0414632B1, and isocyclosporin in World Laid-open Patent Publication No. 93/17039). In addition, U.S. Pat. No. 5,807,820 and U.K. Patent No. 2,218,334A disclose an enhanced transdermal absorption of cyclosporin for the use of cyclosporin as a treatment of alopecia. However, the serious immunosuppressive side effects associated with cyclosporin A do not justify its general use for trichological purposes. Accordingly, there is need for nonimmunosuppressive cyclosporin derivatives useful as hair revitalizing compounds.
In view of the forgoing problem in the prior art, an object of the present invention is to provide nonimmunosuppressive cyclosporin A derivatives of which the hair growth-stimulating effects are maintained while a degree of immunosuppression is lost, through various molecular changes of cyclosporin molecule, on the basis of the current discoveries that the hair growth-stimulating effects do not necessarily correlate with the immunosuppressive activity of cyclosporin molecules (Iwabuchi et al., J. Dermatol. Sci., 1995; 9; 64-69).
As an approach similar to this, studies on derivatives in which suppression of the human immunodeficiency virus (HIV) is maintained while a degree of immunosuppression is decreased are actively being pursued, particularly with derivatives in which the MeLeu group at the position 4 is replaced by a variety of N-methylated amino acid, for example xcex3-hydroxy-methylleucine, methylisoleucine, methylvaline, methylthreonine, methylalanine, which have been reported in patents (European Patent No. 484281 A2, U.S. Pat. Nos. 5,767,069, 5,981,479) and literature (J. Virol., 1995; 69: 2451-2461, J. Antibiotics, 1996; 49: 781-787) as new anti-HIV preparations.
As a result of studies of the inventors for attaining the nonimmunosuppressive cyclosporine derivatives for a new hair growth stimulator, it has now been found that [xcex3-hydroxy-methylleucine4] cyclosporin A is the only one in which a degree of immunosuppression is lost while the hair growth stimulating effect is uniquely maintained among various derivatives including a derivative in which the original No. 4 amino acid, methylleucine, is substituted with the similarly structured xcex3-hydroxy-methylleucine, methylisoleucine, methylvaline, methylalanine, leucine, or isoleucine and [Des-MeLeu4]-cyclosporin A, [Des-MeLeu4, Des-Val5]-cyclosporin A, and others, thereby accomplishing the present invention.
The present invention provides the methods and pharmaceutical compositions for treating alopecia and promoting hair growth using nonimmunosuppressive [xcex3-hydroxy-methylleucine4] cyclosporin A, which is excellent in hair growth and hair loss protecting effect on human hair, represented as in the following Chemical Formula 1, in which the hydroxyl group is added to the carbon position of No. 4 methylleucine of cyclosporin A by a microbial metabolic procedure. xe2x80x9cTreating alopecia and promoting hair growthxe2x80x9d refers to maintaining, inducing, stimulating, accelerating, or revitalizing the germination of hair. 
where MeBmt is N-methyl-(4R)-4-[(E)-2-butenyl]-4-methyl-L-threonine; Abu is L-aminobutyric acid; Sar is Sarcosine; HMeLeu is xcex3-hydroxy-methylleucine; Val is L-valine; MeLeu is N-methyl-L-leucine; Ala is L-alanine; DAla is D-alanine; and MeVal is N-methyl-L-Valine.
Furthermore, the present invention provides pharmaceutical compositions in the form of a liquid phase, a spray, gel, paste, emulsion, cream, conditioner, or shampoo which comprises an effective amount of [xcex3-hydroxy-methylleucine4] cyclosporin A for treating alopecia or promoting hair growth on the skin of mammals and, in particular, on human skin.